Thorn 400w Kolorarc MBIF/H. First power up in 37 years.

Fired up this lovely NOS Thorn MBIF Kolorarc halide lamp tonight.
Fired right up on a plain 400w mercury choke.
Stayed really yellow for a couple of minutes but then the colour temperature increased to a lovely crisp cool white colour with very good CRI.
Quite bright too!